This invention relates to a liquid jetting apparatus having a head capable of jetting a drop of liquid from a nozzle. In particular, this invention is related to a liquid jetting apparatus having a head of jetting a plurality of drops of liquid from a nozzle wherein respective volumes of the plurality of drops of liquid may be different.
In a ink-jetting recording apparatus such as an ink-jetting printer or an ink-jetting plotter (a kind of liquid jetting apparatus), a recording head (head) can move in a main scanning direction, and a recording paper (a kind of recording medium) can move in a sub-scanning direction perpendicular to the main scanning direction. While the recording head moves in the main scanning direction, a drop of ink can be jetted from a nozzle of the recording head onto the recording paper. Thus, an image including a character or the like can be recorded on the recording paper. For example, the drop of ink can be jetted by causing a pressure chamber communicating with the nozzle to expand and/or contract.
The pressure chamber may be caused to expand and/or contract, for example by utilizing deformation of a piezoelectric vibrating member. In such a recording head, the piezoelectric vibrating member can be deformed based on a supplied driving-pulse in order to change a volume of the pressure chamber. When the volume of the pressure chamber is changed, a pressure of the ink in the pressure chamber may be changed. Then, the drop of ink is jetted from the nozzle.
In such a recording apparatus, a driving signal consisting of a series of a plurality of driving-pulses is generated. On the other hand, printing data including level data (gradation data) can be transmitted to the recording head. Then, based on the transmitted printing data, only necessary one or more driving-pulses are selected from the driving signal and supplied to the piezoelectric vibrating member. Thus, a volume of the ink jetted from the nozzle may be changed based on the level data.
In detail, for example, a ink-jetting printer may be used with four level data including: a level data 00 for no dot, a level data 01 for a small dot, a level data 10 for a middle dot and a level data 11 for a large dot. In the case, respective volumes of the ink corresponding to the respective level data may be jetted.
However, recently, it is requested to satisfy user""s various demands with only one ink-jetting recording apparatus. That is, it is requested that one ink-jetting recording apparatus can achieve a plurality of detailed demands, for example recording with high quality, recording at a high speed with not low quality or the like.
Some conventional ink-jetting recording apparatuses can achieve to improve quality of printed images by changing volumes of jetted ink based on a plurality of level data. However, in the conventional ink-jetting recording apparatuses, the number of the plurality of level data is too small to satisfy various detailed demands.
The number of bits of level data may be uniformly increased in order to set the volumes of jetted ink in detail. However, when printing data include the increased number of bits of level data, it needs a longer time to transmit the printing data to the recording head, which results in a low recording speed.
A clock for transmitting the printing data may be one for a higher speed in order to shorten the time for transmitting the data. However, the clock for the higher speed needs to use devices operable with a higher frequency, which results in larger consumed power and/or a more cost.
The object of this invention is to solve the above problems, that is, to provide a liquid jetting apparatus such as an ink-jet recording apparatus that can satisfy user""s various demands by effectively using a plurality of level data, even when the number of the plurality of level data is small.
In order to achieve the object, a liquid jetting apparatus includes: a head having a nozzle; a pressure-changing unit for causing pressure of liquid in the nozzle to change in such a manner that the liquid is jetted from the nozzle; a jetting-mode setting unit for setting a selected jetting mode from a plurality of jetting modes; a level-data setting unit for setting a selected level data from a plurality of level data, based on a jetting data; a driving-signal generator for generating a driving signal, based on the selected jetting mode; a driving-pulse generator for generating a driving pulse based on the selected level data and the driving signal; and a main controller for causing the pressure-changing unit to operate, based on the driving pulse; wherein driving pulses generated based on a selected jetting mode and respective selected level data are different from driving pulses generated based on another selected jetting mode and the respective selected level data.
According to the feature, the driving signal is generated based on the selected jetting mode, and the driving pulse is generated based on the driving signal and the selected level data based on the jetting data. Thus, a manner of jetting the liquid by the driving pulse may be controlled by two factors of the jetting mode and the level data, which may enable to satisfy the user""s various demands.
Preferably, volumes of the liquid jetted from the nozzle based on respective driving pulses are different according to respective jetting modes with respect to a same level data and different according to respective level data with respect to a same jetting mode.
According to the feature, since the volumes of the liquid jetted from the nozzle are different, a jetting speed and/or jetting quality may be controlled more effectively.
In detail, for example, the driving signal may be a periodical signal including a plurality of pulse-waves; and the driving pulse generator is adapted to generate a rectangular-pulse row corresponding to a period of the driving signal based on the selected level data, and generate an AND signal of the rectangular-pulse row and the driving signal as the driving pulse. In the case, quick signal processing can be achieved.
Preferably, the plurality of jetting modes may include a first jetting mode,
the plurality of level data include a small-dot data, a middle-dot data and a large-dot data,
the driving signal generated based on the first jetting mode is a periodical signal including n separated small-drop pulse-waves, each of which is for jetting a small drop of the liquid from the nozzle, n being not less than three, and
the driving-pulse generator is adapted to generate, based on the driving signal generated based on the first jetting mode:
a driving-pulse including only p small-drop pulse-waves when the selected level data is the small-dot data, p being one or more,
a driving-pulse including only q small-drop pulse-waves when the selected level data is the middle-dot data, q being more than p, and
a driving-pulse including r small-drop pulse-waves when the selected level data is the large-dot data, r being more than q and not more than n.
Alternatively, the plurality of jetting modes may include a first jetting mode,
the plurality of level data include a small-dot data, a middle-dot data and a large-dot data,
the driving signal generated based on the first jetting mode is a periodical signal including three separated small-dot pulse-waves, each of which is for jetting a small-dot drop of the liquid from the nozzle, and
the driving-pulse generator is adapted to generate, based on the driving signal generated based on the first jetting mode:
a driving-pulse including only one small-dot pulse-wave when the selected level data is the small-dot data,
a driving-pulse including only two small-dot pulse-waves when the selected level data is the middle-dot data, and
a driving-pulse including all the three small-dot pulse-waves when the selected level data is the large-dot data.
These first jetting modes are suitable for jetting at a high speed.
Preferably, the plurality of jetting modes may include a second jetting mode,
the plurality of level data include a small-dot data, a middle-dot data and a large-dot data,
the driving signal generated based on the second jetting mode is a periodical signal including:
a small-dot pulse-wave for jetting a small-dot drop of the liquid from the nozzle,
a middle-dot pulse-wave for jetting a middle-dot drop of the liquid from the nozzle, and
a large-dot pulse-wave for jetting two or more drops of the liquid from the nozzle, the two or more drops corresponding to a large-dot drop, and
the driving-pulse generator is adapted to generate, based on the driving signal generated based on the second jetting mode:
a driving-pulse including only the small-dot pulse-wave when the selected level data is the small-dot data,
a driving-pulse including only the middle-dot pulse-wave when the selected level data is the middle-dot data, and
a driving-pulse including only the large-dot pulse-wave when the selected level data is the large-dot data.
Alternatively, the plurality of jetting modes may include a second jetting mode,
the plurality of level data include a small-dot data, a middle-dot data and a large-dot data,
the driving signal generated based on the second jetting mode is a periodical signal including:
a small-dot pulse-wave for jetting a small-dot drop of the liquid from the nozzle, and
a middle-dot pulse-wave for jetting a middle-dot drop of the liquid from the nozzle, the middle-dot pulse-wave being separated from the small-dot pulse-wave, and
the driving-pulse generator is adapted to generate, based on the driving signal generated based on the second jetting mode:
a driving-pulse including only the small-dot pulse-wave when the selected level data is the small-dot data,
a driving-pulse including only the middle-dot pulse-wave when the selected level data is the middle-dot data, and
a driving-pulse including both the small-dot pulse-wave and the middle-dot pulse-wave when the selected level data is the large-dot data.
Alternatively, the plurality of jetting modes may include a second jetting mode,
the plurality of level data include a small-dot data, a middle-dot data and a large-dot data,
the driving signal generated based on the second jetting mode is a periodical signal including:
a small-dot pulse-wave for jetting a small-dot drop of the liquid from the nozzle,
a middle-dot pulse-wave for jetting a middle-dot drop of the liquid from the nozzle, the middle-dot pulse-wave being separated from the small-dot pulse-wave, and
an additional large-dot pulse-wave for jetting a second drop of the liquid from the nozzle, a combination of the second drop and the middle-dot drop corresponding to a large-dot drop, and
the driving-pulse generator is adapted to generate, based on the driving signal generated based on the second jetting mode:
a driving-pulse including only the small-dot pulse-wave when the selected level data is the small-dot data,
a driving-pulse including only the middle-dot pulse-wave when the selected level data is the middle-dot data, and
a driving-pulse including both the middle-dot pulse-wave and the additional large-dot pulse-wave when the selected level data is the large-dot data.
These second jetting modes are suitable for jetting at a middle speed with high quality.
Preferably, the plurality of jetting modes may include a third jetting mode,
the plurality of level data include a small-dot data, a middle-dot data and a large-dot data,
the driving signal generated based on the third jetting mode is a periodical signal including:
a small-dot pulse-wave for jetting a small-dot drop of the liquid from the nozzle,
a middle-dot pulse-wave for jetting a middle-dot drop of the liquid from the nozzle, and
a large-dot pulse-wave for jetting a large-dot drop of the liquid from the nozzle, and
the driving-pulse generator is adapted to generate, based on the driving signal generated based on the third jetting mode:
a driving-pulse including only the small-dot pulse-wave when the selected level data is the small-dot data,
a driving-pulse including only the middle-dot pulse-wave when the selected level data is the middle-dot data, and
a driving-pulse including only the large-dot pulse-wave when the selected level data is the large-dot data.
The third jetting mode is suitable for jetting with super-high quality.
In addition, preferably, the pressure-changing unit has a piezoelectric vibrating member.
The liquid may be an ink. In the case, the ink may include a colorant and an organic solvent. A density of the colorant is preferably 0.1 to 10% by weight. Furthermore preferably, the colorant includes a pigment or a dye. Alternatively, the colorant is preferably a pigment which has particles of 20 to 250 nm diameter. In addition, preferably, a viscosity of the ink is 1 to 10 cps. A surface tension of the ink is preferably 25 to 60 mN/m. The ink preferably includes water.
In addition, a controlling unit for controlling a liquid jetting apparatus including a head having a nozzle, and a pressure-changing unit for causing pressure of liquid in the nozzle to change in such a manner that the liquid is jetted from the nozzle, comprises: a jetting-mode setting unit for setting a selected jetting mode from a plurality of jetting modes; a level-data setting unit for setting a selected level data from a plurality of level data, based on a jetting data; a driving-signal generator for generating a driving signal, based on the selected jetting mode; a driving-pulse generator for generating a driving pulse based on the selected level data and the driving signal; and a main controller for causing the pressure-changing unit to operate, based on the driving pulse; wherein driving pulses generated based on a selected jetting mode and respective selected level data are different from driving pulses generated based on another selected jetting mode and the respective selected level data.
A computer system can materialize the whole controlling unit or only one or more components in the controlling unit.
This invention includes a storage unit capable of being read by a computer, storing a program for materializing the controlling unit in a computer system.
This invention also includes the program itself for materializing the controlling unit in the computer system.
This invention includes a storage unit capable of being read by a computer, storing a program including a command for controlling a second program executed by a computer system including a computer, the program is executed by the computer system to control the second program to materialize the controlling unit.
This invention also includes the program itself including the command for controlling the second program executed by the computer system including the computer, the program is executed by the computer system to control the second program to materialize the controlling unit.
The storage unit may be not only a substantial object such as a floppy disk or the like, but also a network for transmitting various signals.